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Stripping a benq dw1620

alf638

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First this is just the same as the email I sent you but I did both in case you checked one before the other.:yh:

Hi, yeah thats the one I was talking about. I think it uses lm1117 although I could not tell you for sure. Also, you will notice in the diagram it has a current regulator (also known as a potentiometer), this is used to adjust the current going to the laser diode. To test the current you will need a multimeter and a test load. I have added links to the multimeter I use and a good looking test load. You'll find more instructions on testing the current on the other links I gave you on the forum. And so you know, this driver should fit inside a module easily, all you will need to do is solder the diode to it and solder leads to the batteries. The website with the testload also sells good cheap modules.
I hope i've helped and if you're still confused feel free to email whenever:)



New LCD Digital Voltmeter Ammeter Ohm Multimeter DT830B (eBay item 250541801815 end time 27-Jan-11 18:20:58 AEDST) : Industrial
Laser Diode Driver Test Load KIT *MUST HAVE* [Stonetek_RKCSTR_TL] - $10.99 : StoneTek Electronics, Your Laser Parts Store
 





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For first build I'd advise against using potenciometers, Alf.

There is a simple way of setting the current for your driver - solder one fixed resistor.
Current output is determined by resistance between OUT and ADJ pins. How do you achieve that resistance is not exactly important (fixed resistor, or trimmer).

You can calculate the current you need and put one resistor and call it done.

Formula for that would be :
1.25 / Current desired in Amperes = Resistance in Ohms.

Don't put miliamperes there. If you need, for example, 100mA, don't put 100 , put 0.1 .
 

alf638

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True, but personally I've always liked using potentiometers for some reason, no idea why I just like them.
 
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Obviously so. I'd still get 50 pieces if I were you, one can never have enough of those things. $10 is not a lot for 50 LM regulators, free shipping too.
 

rhd

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Ok - You've sold me on 50x. So what, if anything, do we loose over the LM317?

There's a max limit of 1A, versus 1.5A on the LM317. That's the only major disadvantage I could see. But if you needed more than 1A, you could run 2x LM1117 setups in parallel right?
 
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Exactly.

Those are SMD variants and are limited in dissipating heat, so that's why they are advised to be ran at 1A maximum.

If you need more than 1A then you're not looking for linear SMD ICs anyhow.
 

rhd

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Cool -

Any experience making drivers with the LM358? I've noticed a number of commercial drivers using this IC, and it IS available in a DIP package.
 

Userro

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Here I am again, driver board has arrived and I should be ready to compose a working laser.
Here is what I got:
35hhgmx.jpg
and I'm equipped with a solder and a voltmeter, I have yet to clean the back of the diode from the leftout metal.
Also the driver seems a little different from the one I have ordered a month ago, is it ok in your opinion?
 
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It would seem that the board is not properly cut. Just remove the leftmost side of it, where there are no components, I see a cut there, it's just that it didn't snap. Should not be too difficult.

Back of the diode? If there is no excess solder, and nothing is bridged together, you don't have to worry about it.

What specifically do you need help with?
 

Userro

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Well, the driver won't fit in the axis module I think, even if further cut. But that's not a big problem, I think.
Then I'll have to solder two wire to the diode and two for a battery, am i right?
Also about the driver, will I have to fix the current as previously said?
 

rhd

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Yes - you will still need to set the current, with a test load attached.
 
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Also, you will not need to cut any wires for diode. Just simply solder it to the diode as it should be, pads on PCB are physically made to fit the diode in right order.

And yes, current will need to be preset. You have a test load?
 




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